According to the Canadian Press, Desiree Haight was worried it was “a relapse of a condition she was afflicted by in 2005, when she was hospitalized for three months and needed a feeding tube, eventually dropping to a body weight of just 98 pounds.”

“They couldn’t find anything [after] batteries and batteries of tests,” she told the Canadian Press of her hospitalization 14 years ago. “The psychiatrist said I was stuck in a fight-or-flight mode.”

But this time, doctors diagnosed her quickly. It wasn’t food poisoning or a nasty virus — but rather cannabinoid hyperemesis syndrome (CHS).

The condition is characterized by abdominal pain and recurrent episodes of severe nausea and uncontrollable vomiting, and it’s associated with regular, heavy cannabis use.

With recreational cannabis now being legal in Canada, we could start to hear more about the syndrome. Even though it was first described in medical literature in 2004, it’s only been in the last few years that it’s started to get more widespread attention.

Joseph Finkler, an emergency physician at St. Paul’s Hospital in Vancouver, says he sees the condition every few weeks or months, although Health Canada hasn’t started tracking it yet.

He suspects that in the past, doctors may have mistaken CHS for cyclical vomiting syndrome. Patients with the latter are more likely to have a history of psychiatric illness and a personal or family history of migraines, according to a 2015 study published in the Canadian Medical Association Journal.

That study found that people with CHS have a history of daily use of natural or synthetic cannabis over a period of years. They experience incapacitating vomiting that sometimes happens more than 20 times a day and can last from 24 to 28 hours. Other research notes that retching can last as long as 48 hours.

Patients with CHS may have numerous visits with a doctor before getting diagnosis, the CMAJ study found, highlighting the syndrome’s underrecognition.

Besides chronic cannabis use, another distinguishing feature of the syndrome (and one that’s poorly understood) is that symptoms are alleviated by bathing with hot water.

“People [with CHS] will self-medicate with hot showers,” Finkler says. “All other problems, like bowel obstruction or being sick from eating contaminated food, would not be alleviated by going in the shower. It’s almost a diagnostic criterion. GI [Gastro-intestinal] doctors would nail this diagnosis in a couple of minutes.”

Anytime someone presents in ER with severe vomiting, other conditions have to be ruled out, such as pancreatitis or intestinal obstruction or perforation. Finkler would ask about fever, diarrhea, signs of infection, migraines, blood or mucus in stool, and night sweats as part of the diagnosis, symptoms that don’t typically accompany CHS.

“If there are no other signs and they’re presenting with just nausea and vomiting, we now inquire as to whether they are using cannabis and how much are they using,” Finkler says.

The cause of the syndrome isn’t certain, though it appears to have to do with the brain-gut connection. Heavy cannabis use results in the accumulation of tetrahydrocannabinol (THC), the substance’s active compound, in fatty issues. That leads to stimulation of the intestines that overrides the effects of the central nervous system, according to the CMAJ study.

“My report was prompted when I saw a patient in the emergency department with unstoppable nausea and vomiting that was not responding to usual treatments of anti- nausea medications and who did not seem to fit the diagnostic criteria for an illness causing vomiting and nausea, such as a viral gastroenteritis, or pancreatitis,” says Dr. Chelsey King, coauthor of the CMAJ study. “Unfortunately, it is not well understood why a hot shower alleviates symptoms. Theories propose that cannabis interferes with the body’s normal thermoregulatory mechanism, but again, no one knows.”

It’s also unclear whether the mechanism of ingestion (smoking cannabis versus consuming it in edible form, for instance) makes a difference in terms of effects or prevalence of the syndrome.

To treat CHS, doctors might prescribe anti-nausea medication, such as ondansetron, which is used to counter nausea in patients receiving chemotherapy. Relief has been reported with lorazepam, a benzodiazepine, and haloperidol, an antipsychotic drug.

People rarely have to be admitted to hospital, but it does happen if there’s severe dehydration, electrolyte disturbance, or acute renal failure.

“Sometimes people get so sick and almost disorganized with delirium,” Finkler says. “Some people we hold for eight or 12 hours to give them IV fluids and anti-emetics [drugs for nausea and vomiting].”

Researchers are also looking at the benefits of topical capsaicin cream, which contains the molecule that is active in hot peppers.

A 2017 study in the journal Clinical Toxicology found that 13 patients who had been diagnosed with CHS in two medical centres in the U.S. experienced symptom relief after the administration of capsaicin cream after other treatments failed.

Cessation of cannabis also resolves symptoms.

That Calgary woman has no plans to take up cannabis again anytime soon.